Field of the Invention
The subject invention relates generally to systems and methods for monitoring fluid pressure and fluid flow within pressurized cable networks and, more particularly, to systems for monitoring and tracking the age of air pressure and/or air flow alarm conditions detected by monitoring systems that monitor the air pressure and air flow within pressurized telecommunication cable networks.
The cables that make up a telecommunications network typically include a sheath made of a water-resistant or waterproof material, such as lead or polyethylene. These sheaths typically encompass wires, such as copper wires, and an insulation material that separates individual conductor pairs. This insulation material may be, for example, paper, pump, or plastic.
Exposure of the interior of a cable to water or moisture may lead to a number of problems. For example, exposure of the interior of a cable to moisture may destroy the insulating characteristics of the paper or pump. If cracks develop in the sheath of a cable or the sheath of a cable is sliced, water may enter the cable and electrolysis may occur, resulting in faulted conductor pairs.
Each year, telecommunication companies spend large amounts of money pumping low-humidity air into their cables and pipes that carry and enable the transmission of voice and data information. This low-humidity air creates positive pressure within the cable sheaths, enabling them to resist standing water, moisture damage, and the like. Such standing water and moisture damage may lead to noise on the line, data transmission errors, and, ultimately, complete cable failure. Thus, the basic premise of cable pressurization is to keep the pressure within a cable in excess of the pressure that could be applied by standing water. To this end, telecommunications companies and related industry associations have established minimum air pressure standards for underground, direct-buried, and aerial cables. For example, a minimum air pressure of six (6) pounds per square inch (PSI) may be required for underground cables, a minimum air pressure of three (3) PSI may be required for direct-buried cables, and a minimum air pressure of one (1) PSI may be required for aerial cables, as they are less at risk from water damage.
The air pumped into pressurized telecommunications cables originates from a plurality of air compressors, typically located in a company""s xe2x80x9ccentral officesxe2x80x9d or other facilities. These air compressors are preferably coupled with dryers or dehumidifiers operable for removing residual moisture from the air. Because a pressurized cable route may include a plurality of discrete sections of cable, each potentially thousands of feet long, the air pressure tends to decrease as the distance from a central office, and a given air compressor, increases. This pressure drop is due, in part, to the presence of inevitable leaks. Therefore, air pressure is typically reestablished along a cable route by running an air pipe along the route and introducing air at a plurality of fixed points. The air pipe is connected to a plurality of manifolds that distribute air to the cables at, for example, each utility bole, making these connections easier to maintain.
In order to maintain a pressurized cable route, a plurality of air pressure and flow monitoring devices or sensors are placed at strategic points along the route (for example, at each manifold). These sensors are typically standard pressure transducers. The air pressure sensors measure the amount of air compression in a given cable volume at a given time in PSI. The flow sensors measure the standard cubic feet of air to pass through a given cable volume in a given period of time in standard cubic feet per hour (SCFH) or standard cubic feet per day (SCFD). Both the air pressure sensors and the flow sensors are linked to monitors in the various central offices so that readings may be taken by maintenance technicians at predetermined times. If the air pressure or flow level for a given sensor drops below a predetermined value, an alarm is tripped. A maintenance technician may then be dispatched to repair the affected cable, air pipe, manifold, etc.
Those who manage the pressurized cable route may collect data from the various central offices and, using existing software programs, analyze maintenance expenditures, track maintenance technician efficiency, identify problems, and rate overall pressurization system quality. This is typically done hierarchically, e.g., by region, district, office, area, and the like. These software programs, such as that used by GTE (the xe2x80x9cGTE Air Pressure Status Reportxe2x80x9d), typically generate summary information related to such items as the number of air pressure and flow alarms for a given period of time, the number of maintenance technician dispatches for a given period of time, a pressurization system quality index (SQI), the total man-hours for a given period of time or per sheath-mile, the operation of given air compressors or dryers, and problem regions, districts, offices, areas, etc. Although marginally useful, this information is typically complex, often inaccurate, and generally expensive to collect. More importantly, this information is dependent upon the schematics of a given pressurized telecommunications cable route, and must take the network layout into account.
Also, many of the reports generated by such systems fail to indicate when an alarm has occurred and how long the alarm condition has been in existence without being remediated. Thus, although the report may indicate that an alarm has occurred, the manager responsible for maintaining the system does not know when it occurred and, perhaps more importantly, is unable to ascertain how long the alarm condition has existed without being rectified. Without such information, a manager is unable to prioritize repair activities in the order of alarm occurrence. Thus, there is a need for systems and methods that provide inexpensive and accurate information related to the age of pressure and/or flow alarm conditions occurring in pressurized cable networks.
In accordance with one embodiment of the present invention, there is provided a method of monitoring pressurization performance of a cable network that may include detecting alarm conditions within the cable network, recording the time and date during which each alarm condition was initially detected, and calculating a length of time for each detected alarm condition during which the detected alarm condition remains unremediated.
Accordingly, the various embodiments of the present invention provide management with tools for monitoring the remediation progress and prioritization of alarm conditions occurring within networks of pressurized cables. Those of ordinary skill in the art will readily appreciate, however, that these and other details, features and advantages will become further apparent as the following detailed description of the embodiments proceeds.